Press TV- An independent human rights organization says Saudi Arabia has arrested two rights campaigners for their online activities amid unrelenting�crackdown�on free speech in the kingdom.

In a press release published on its website on Tuesday, the [Persian] Gulf Center for Human Rights ([P]GCHR) said Essam Koshak and Ahmed al-Mshikhs were taken into custody last week.

The center voiced grave concern over the arrests as there were no charges against the men, adding that �their online activities� are believed to be the reason behind their detention.

�[P]GCHR believes that these arrests are solely due to the two men exercising their legitimate and peaceful right to freedom of opinion and freedom of expression and conducting their work in the field of human rights,� the rights group added.

Mshikhs, the co-founder of the Al-Adalah Center�for Human Rights in Saudi Arabia, was detained on Thursday in the predominantly�Shia district�of Qatif. He had tweeted a Nativity scene showing the birth of Christ�on Christmas Day.

Koshak, who describes himself as a rights defender, was nabbed in Mecca on Sunday. He had tweeted Western media reports about Saudi Arabia and re-tweeted posts from the banned Saudi Civil and Political Rights Association.

The Riyadh�regime is under fire for its dire rights record inside and outside the kingdom.

However, Saudi Arabia's membership in the United Nations Human Rights Council�was renewed last year despite widespread criticisms.

The country has a high number of executions and disappointing�women's rights record while banning the public�practice of�any form of religion other than Islam.

Saudi Arabia is also widely seen as a major sponsor of Takfiri terrorists wreaking havoc mainly in the Middle East region. It is also waging a deadly aggression against neighboring Yemen.